Hi,
When I activate the curves for the Lab channels in the Lab Adjustment module, the histogram for the L* channel shows up OK but doesn’t for the a* or b* channels. There is no histogram either for the CL and the LC curves, but there is one for the CC curve. I’m not sure whether this is normal or if there is a problem. I use the daily v5.5 builds.
Any help would be appreciated.

OK thanks. The Rawpedia entries for the CL and LC curves show histograms in the example images in fact so I thought I had missed something.
The reason I asked about the a* and b* channel histograms was that I was experimenting with the following technique: https://petapixel.com/2017/09/14/using-lab-color-photoshop-add-color-punch-images/
However thinking about it, this may be simply what the chromaticity slider does anyway?